The present invention relates generally to oceanographic apparatus and, more particularly, to a water sampler for obtaining uncontaminated samples of near-bottom liquids for analytical studies. The sampling apparatus is adapted to be lowered into lakes, rivers, and the like for the purpose of collecting samples of water which can then be examined with regard to their oxygen content as well as the content of other substances suspended or dissolved therein. The samples obtained must be of sufficient volume and free of contamination to represent reliably the water composition being sampled. Also, the need for aseptic sampling has long been recognized in bacteriological studies.
The study of near-bottom water in bodies of water like lakes and oceans has become quite important in recent years due to an increased understanding of the unique chemical and biological reactions which take place at the mud-water interface. Samples of water taken from this zone generally contain chemical and biological species which are changed or diluted beyond detection as they are mixed with the entire body of water. Since this water has considerable biological and health related impacts, it is desirable to sample and analyze the water lying quite close to the bottom, for example, within one or two inches of the bottom.
In the past, samples had been taken close to a bottom of a body of water by using sampling apparatus designed to draw water at any particular depth and by suspending such apparatus near the bottom to obtain the desired sample. This led to uncertainty of actual sampling depths, since sampling personnel could not actually observe the sampler in operation. This practice also led to disturbing the bottom by impact by the sampler with the resultant taking of a non-representative sample. Near-bottom samples have also been taken using a pump and hose, but this system has the same inherent drawbacks.